Re: Grounding Problem???

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Ed,

On 25 Jan 2002, at 15:07, Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Esondrmn-at-aol-dot-com>
> 
> In a message dated 1/24/02 6:14:35 PM Pacific Standard Time, tesla-at-pupman-dot-com
> writes: 
> 
> 
> >
> > Hi John, Scot, All 
> > > 
> > >     I have tried loosening the coupling quite a bit.  To get rid of the 
> > > racing sparks the coupling must be around 0.08.  Spark length is pitiful 
> > > in that case.  I have tuned the coil as well as I can.  The tuning point 
> > > is about 1.5 turns in from the calculated point.  Moving the tap just 
> > > decreases spark length.  I am running a 6 inch coil using two of those 
> > > GE copier xfmrs for a supply.  I'm using a 0.1 uF cap, for a bang size 
> > > of approx. 5 joules.  My specs are in the "Help! suicidal secondary" 
> > > thread, except that I'm now using a smaller toroid of 6" by 22".  I 
> > > tried a 0.066 uF cap, but racing sparks remain.  Spark length goes in 
> > > the toilet too.  On a good humid night, I can get a few 6 ft. strikes to 
> > > the ground.  Dry nights give short streamers, and long racing sparks 
> > > :-(.  I can't believe that I could be overpowering an epoxy coated 6 by 
> > > 28 inch secondary with 1600 VA. 
> >
> > It is not a power problem but an energy one. 5J is developing too 
> > high a voltage for a secondary that size (and length in particular). 
> > I'm getting 5'+ from a 4' tall secondary using around 4J/bang and not 
> > a hint of racing sparks. Not only is the taller secondary able to 
> > handle higher voltages but it is developing lower voltages for the 
> > same energy as well. 
> >
> > Regards, 
> > Malcolm 
> 
> 
> 
> Malcolm, 
> 
> I have a similar sized secondary, 6" diameter with a winding length of 27.6"
> using 22 guage wire.  I am using a .05 mfd cap with a 14, 400 volt
transformer
> running about 7 kva.  If I did the math correctly, the bang size here is 11
> joules.  This coil runs fine with a sync rotary at 240 bps.  If I try to
run it
> at 120 bps, I get a very intense and visible corona between primary and
> secondary, with small sparks coming out of the middle of the secondary,
and it
> looks like it is ready to blow up.  In order to run at 120 bps, I would
need to
> reduce my coupling to be safe. 
> 
> Ed Sonderman

Is that energy the same at the higher breakrate? Also, what size 
terminal are you using?

Regards,
malcolm